Well, you might be asking the wrong question as Pres. Herbert Hoover did not serve in Lyndon Johnson’s administration. Hoover worked under Truman, the successor of his adversary FDR, and Eisenhower. The two presidents appointed Hoover to head the Commission on Organization of the Executive Branch of the Government (Hoover Commission) to recommend administrative changes in the Federal Government of the United States. Hoover was appointed by Truman as they became friends. He was again appointed by Eisenhower in 1947, and he was 80 years old at that time.